1. Field of the Invention
The present invention relates to a full-color toner cartridge applicable to electrophotographic duplicators, printers, facsimiles, etc., to a method of supplying toner from the cartridge into developing units, and to a method of filling toner into the toner cartridge.
2. Description of the Related Art
For supplying a fresh toner to a developing unit, widely used is a toner cartridge, as being easy to handle and enabling easy toner supply to the unit without scattering the toner. The toner cartridge functions as a toner container before it is fitted into a developing unit, and, after having been fitted thereinto, it functions as a toner supply tank.
As in FIG. 1 and FIG. 2, the toner cartridge is generally provided with a cartridge body 1, a spiral agitator (agitating and conveying member) 2, a coupling member 3 and a sealing member 4.
The cartridge body 1 is provided with a cylindrical container with its both ends being sealed with side walls 1b and 1bxe2x80x2, and has a toner outlet port 1c through the side wall adjacent to either one of right and left side walls, for example, adjacent to the side wall 1bxe2x80x2 as illustrated.
The spiral agitator 2 is rotatably so disposed in the cartridge body 1 that it can rotate to agitate the toner therein while conveying it toward the outlet port 1c for development.
The coupling member 3 has a shaft 3a that rotatably runs through the other side wall 1b into the cartridge body 1, and a coupling part 3b that is positioned outside the side wall 1b and is connected with a driving source (not shown). With these, the coupling member 3 is connected with the agitator 2 to transmit the driving power from its source to the agitator 2.
The sealing member 4 is fixed to the inner surface of the side wall 1b of the cartridge body 1, and is so disposed that it has a through-hole 4a through which the shaft 3a of the coupling member 3 is airtightly and rotatably runs into the cartridge body 1 in the sealed region, and that it seals the gap between the shaft 3a and the side wall 1b of the cartridge body 1 through which the shaft 3a runs into the cartridge body 1.
Heretofore, black toner contains wax having a relatively high melting point, such as polyethylene, polypropylene or the like, for ensuring good offset resistance in fixation. However, such a high-melting-point wax is unfavorable to full-color toner, as often detracting from the transparency of OHP images and often requiring relatively high temperature fixation. Accordingly, wax is not added to full-color toner. In place of it, a liquid of silicone oil or the like is applied to the surface of a thermal fixation roller for preventing offset in fixation. This method will be extremely effective for easily releasing the image-printed media from the fixation roller with no trouble of offsetting, but is often problematic in that it requires a large-sized fixation unit and that the image-printed media are sticky.
In that situation, desired is oilless full-color toner that contains wax for full-color image formation.
Toner cartridges used these days have a complicated structure and are expensive. Therefore, the amount of the toner to be filled into them is desired to be as large as possible in order to reduce the printing cost per one print. Accordingly, toner cartridges are so designed that the cartridge capacity could be as large as possible.
However, in case where toner cartridges are so designed that they could be filled with an enlarged amount of toner or the diameter of the cartridge body is enlarged, the powder pressure in the cartridges shall increase. In particular, when such toner cartridges are left in a high-temperature and high-humidity atmosphere for a long period of time, then the contact surface of the toner particles therein will increase and the toner particles will block together. Such toner blocking is unfavorable. If toner particles in a cartridge block together, the toner could not be well conveyed to a developing unit, and even if conveyed thereto, the blocked toner lumps still remain as they are without being crushed, thereby causing color steaks and other image defects in the images formed. In particular, full-color toners containing low-melting-point wax will aggregate owing to the low-melting-point wax therein, and will therefore readily block while in cartridges.
The present invention is to solve the problems noted above. Specifically, the invention is to provide a full-color toner cartridge free from toner blocking therein and ensuring stable high-quality image formation; a method of supplying toner from the cartridge to a developing unit; and a method of filling toner into the toner cartridge.
We, the present inventors have assiduously studied and, as a result, have found that the aims of the invention can be attained by the following:
 less than 1 greater than  A full-color toner cartridge detachable from a developing machine, the cartridge including a cylindrical container having an opening for toner discharge and an agitating unit and a toner, in which the toner contains wax having a softening point of not higher than 120xc2x0 C. and the following formulae (1) and (2) are satisfied:
A/(Bxc3x97Dxc3x97xcfx80)xe2x89xa6C(C=65)xe2x80x83xe2x80x83(1)
Bxe2x89xa70.5xe2x80x83xe2x80x83(2)
where A indicates the amount of the toner to be filled into the cartridge (g); B indicates the apparent tapped density of the toner (g/cm3); D indicates the inner diameter of the cylindrical container (cm); and xcfx80 indicates the ratio of the circumference of a circle to its diameter.
 less than 2 greater than  A method for filling a toner cartridge with a full-color toner, wherein the toner cartridge has a cylindrical container provided with an opening for toner discharge and is detachable from a developing machine, and the toner to be filled into the container contains wax having a softening point of not higher than 120xc2x0 C. and the following formulae (1) and (2) are satisfied:
A/(Bxc3x97Dxc3x97xcfx80)xe2x89xa6C(C=65)xe2x80x83xe2x80x83(1)
Bxe2x89xa70.5xe2x80x83xe2x80x83(2)
where A indicates the amount of the toner to be filled into the cartridge (g); B indicates the apparent tapped density of the toner (g/cm3); D indicates the inner diameter of the cylindrical container (cm); and xcfx80 indicates the ratio of the circumference of a circle to its diameter.
 less than 3 greater than  A method for supplying toner into a developing unit through the opening of the toner cartridge of above (1).